I watched a video on the T240 walk-thru. Looks like you're talking about the small tabletop next to the bed? If so - my recommendation would be to go to a home improvement store, Lowes/Home Depot. Head to kitchen counter section. They have a selection of DIY countertop replacements. I'd say you can "upgrade" and get enough for both sides of the bed if you want to stay symmetrical/consistent. Good thing is that you can cut to the length and width you want and put the unfinished side against the front wall and side wall.
Goes without saying that I hope you found and fixed the source of the leak?
2012 FunFinder X 210UDS
4-68 watt flexible panels; 1-215 glass panel/4 Battle Born LiFePO4 Deep Cycle Batteries
2014 Ford F350 6.7 Liter PowerStroke V-8 Diesel longbed, SRW